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[PATCH 1/2] migration/xbzrle: use ctz64 to avoid undefined result
From: |
Matheus Tavares Bernardino |
Subject: |
[PATCH 1/2] migration/xbzrle: use ctz64 to avoid undefined result |
Date: |
Tue, 7 Mar 2023 11:48:08 -0300 |
__builtin_ctzll() produces undefined results when the argument is 0.
This can be seen through test-xbzrle, which produces the following
warning:
../migration/xbzrle.c:265: runtime error: passing zero to ctz(), which is not a
valid argument
Replace __builtin_ctzll() with our ctz64() wrapper which properly
handles 0.
Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
---
migration/xbzrle.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/migration/xbzrle.c b/migration/xbzrle.c
index 05366e86c0..21b92d4eae 100644
--- a/migration/xbzrle.c
+++ b/migration/xbzrle.c
@@ -12,6 +12,7 @@
*/
#include "qemu/osdep.h"
#include "qemu/cutils.h"
+#include "qemu/host-utils.h"
#include "xbzrle.h"
/*
@@ -233,7 +234,7 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t
*new_buf, int slen,
break;
}
never_same = false;
- num = __builtin_ctzll(~comp);
+ num = ctz64(~comp);
num = (num < bytes_to_check) ? num : bytes_to_check;
zrun_len += num;
bytes_to_check -= num;
@@ -262,7 +263,7 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t
*new_buf, int slen,
nzrun_len += 64;
break;
}
- num = __builtin_ctzll(comp);
+ num = ctz64(comp);
num = (num < bytes_to_check) ? num : bytes_to_check;
nzrun_len += num;
bytes_to_check -= num;
--
2.39.1